The present invention relates to a power supply system, and more particularly, to a power supply system having AC redundant power sources with DC redundant power supplies.
The contemporary power supply system with DC (direct current) redundant power supplies is depicted in FIG. 1. The power supply system with DC redundant power supplies includes a single AC (alternating current) power source 11 provided to supply AC electric power to operate a plurality of DC power supplies 12, 13, and 14 which are connected in parallel for outputting combined DC electric power. The configuration of the contemporary power supply system with DC redundant power supplies is advantageous over the situation that if one of the DC power supplies which is designated to supply DC electric power in normal operation is failed, the other DC power supplies can supply DC electric power without interruption.
Notwithstanding the advantages of the contemporary power supply system, assuming that the single AC power source 11 is abnormally interrupted in supplying AC electric power to operate the DC power supplies 12, 13, and 14, the operation of the whole power supply system will halt and the power supply system will come into power outage. As a rule, an ideal power supply system must includes not only the functionality of providing auxiliary DC power supplies, but also includes the functionality of providing auxiliary AC power sources to supply AC electric power to operate the DC power supplies in case the main AC power source in operation is abnormally interrupted.
The applicant therefore tried to contrive a power supply system having AC redundant power sources with DC redundant power supplies, to ensure that in case the main AC power source is interrupted in supplying AC electric power to operate the DC power supplies, the other AC power source can act as a redundant AC power source to supply auxiliary AC electric power to operate DC power supplies without interruption.
It is, therefore, an object of the present invention to provide a power supply system having DC redundant power supplies that can sustain supplying DC electric power in event that one of the DC power supplies is failed in supplying DC electric power.
It is still an object of the present invention to provide a power supply system having AC redundant power sources and DC redundant power supplies, to assure that the DC power supplies can sustain supplying DC electric power even if the main AC power source in operation is interrupted.
According to a preferred embodiment of the present invention, the power supply system is arranged to include three DC power supplies which are connected in parallel for outputting a combined DC power output, two AC power sources, each of the AC power sources is directly coupled in series with a corresponding one of DC power supplies to provide an input voltage to operate the corresponding one of the DC power supplies, and a control module coupled between the AC power sources and the DC power supply which is not directly coupled in series with a corresponding one of the AC power sources for creating a conductive path to transfer the input voltage from one of the AC power sources to the DC power supply which is not directly coupled in series with a corresponding one of AC power sources when the other AC power source is abnormally interrupted in supplying an input voltage to operate the DC power supplies.
The control module may comprises a first relay circuit coupled in series with one of the AC power sources for receiving an input voltage from the AC power source and transmitting the input voltage, a second relay circuit coupled in series with one of the AC power sources for receiving an input voltage from the AC power source and transmitting the input voltage, and a third relay circuit which is coupled with the first relay circuit and the second relay circuit and the DC power supply which is not directly coupled in series with one of the AC power sources for alternatively creating a conductive path in response to a control signal to provide either the input voltage being transmitted from the first relay circuit or the input voltage being transmitted from the second relay circuit to the DC power supply coupled therewith.
Both of the above-described first relay circuit and the second relay circuit are implemented by a one-to-one relay element, and the third relay circuit is implemented by a two-to-one relay element. The control module for creating a conductive path for transmitting the input voltage from one of the AC power sources to the DC power supply which is not directly coupled in series with the AC power sources further includes a microprocessor which persistently detects the input voltages from each of the AC power sources and generates a control signal to drive the third relay circuit to create a conductive path to transfer an input voltage from one of the AC power sources to the DC power supply which is coupled with the third relay circuit when the other AC power source is interrupted in supplying an input voltage to operate the DC power supplies, and generate a control signal to restore the conductive path between the interrupted AC power source and the corresponding power supply when the interrupted AC power source becomes normal.
Broadly speaking, the number of the DC power supplies of the power supply system in accordance with the present invention can be indicated in terms of 2N+1, wherein N is a positive integer number, and the number of the third relay circuits should be identical to the number of the DC power supplies each of which is coupled with a corresponding third relay circuit.
Now the foregoing and other features and advantages of the present invention will be more clearly understood through the following descriptions with reference to the accompanying drawings, wherein: